3x^2-6-6x+3x^2-6=0

Solution for 3x^2-6-6x+3x^2-6=0 equation:

3x^2-6-6x+3x^2-6=0

We add all the numbers together, and all the variables

6x^2-6x-12=0

a = 6; b = -6; c = -12;
Δ = b2-4ac
Δ = -62-4·6·(-12)
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-18}{2*6}=\frac{-12}{12}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+18}{2*6}=\frac{24}{12}
=2
$